The invention discloses a chewing gum comprising at least one biodegradable polymer in an amount of from 0.1 % to 95 %, said biodegradable polymer such as herein described having a glass transition temperature (Tg) 38°C to 90°C, wherein said chewing gum comprising said at least one biodegradable polymer further comprises at least one elastomeric compound such as herein described, and wherein said biodegradable polymer has a plasticizing effect on said elastomeric compound.

Full Text

FIELD OF THE INVENTION
The present invention relates to the field of chewing gum. In particular, the present
invention provides a gum base and a chewing gum comprising a biodegradable
polymer having a glass transition temperature (Tg) above 37°C.
TECHNICAL BACKGROUND AND PRIOR ART
It is generally recognized that chewing gum that is dropped in indoor or outdoor
environments gives rise to considerable nuisances and inconveniences due to the fact
that the dropped gum sticks firmly to e.g. street and pavement surfaces and to shoes
and clothes of people being present or moving in the environments. Adding
substantially to such nuisances and inconveniences is the fact that conventional
chewing gum products are based on the use of elastomeric and resinous polymers of
natural or synthetic origin that are substantially non-degradable in the environment.
Cleaning off the dropped chewing gum remnants is often costly and without
satisfactory results.
Attempts to reduce the nuisances associated with the widespread use of chewing gum
have e.g. involved improvement of cleaning methods or incorporation of anti-stick-
ing agents into chewing gum formulations. However, none of these precautions have
contributed significantly to solving the pollution problem.
In recent time an increasing amount of interest has been paid to synthetic polyesters,
which are hydrolysable to smaller compounds, which are more easily degradable by
environmental effects and/or removed via metabolic pathways.

In US 5,672,367 it has been disclosed that chewing gum may be made from certain
synthetic polymers having in their polymer chains chemically unstable bonds that
can be broken under the influence of light or hydrolytically into water-soluble and
non-toxic components. In US 5,672,367 such polymers, which are obtained by the
polymerization of cyclic esters, e.g. lactides, glycolides, and ε-caprolactone, are
referred to as biodegradable. Furthermore according to the same document such
polymers as applied in chewing gum have a glass transition temperature of at most
37°C
The upper limit of the glass transition temperature being substantially at human body
temperature is a general assumption throughout the prior art within the area of biode-
gradable chewing gum polymers. The importance of keeping the glass transition
temperature of chewing gum polymers substantially below human body temperature
seams to be a logical consequence of the basic properties related to the glass tran-
sition temperature (Tg). Usually Tg is loosely defined as the temperature at which a
polymer undergoes a significant change in properties. Accordingly, Tg may be
described as the temperature where a polymer structure turns "rubbery" upon heating
and "glassy" upon cooling.
Therefore, the glass transition temperature is in the prior art of biodegradable
chewing gum polymers generally kept substantially below human body temperature.
An example of such prior art-chewing gum polymer is disclosed in WO 00/19837
wherein it is stated that caprolactone may be toxic and should be avoided as a
masticatory substance. As 'the applied polymer comprises no low-Tg-inducing
monomers, the Tg is found to be too high. Therefore a large amount of plasticizer is
used to obtain a poly(D,L-lactic acid) polymer with a lower Tg. According to WO
00/19837, the Tg is shifted from a higher value to a lower, whereby the resulting
polymer according to WO 00/1983 7-is much more rubbery and elastic.

A drawback of using these large amounts of plasticizer such as triacetin in chewing
gum may be that the robustness of the chewing gum is compromised, especially if
the chewing gum contains rather aggressive chewing gum ingredients such as acids
or fats.
Another approach in order to obtain a combined advantageous texture and a
robustness with respect to gum base or chewing gum components is to mix the
biodedegradable polymer with different kinds of natural resins. The resin compounds
are contributing to obtain the desired masticatory properties and acting as plasticizers
for the elastomers of the gum base composition.
Resin in conventional chewing gum bases typically include synthetic resins such as
polyvinyl acetate (PVA) and natural resins such as rosin esters, which are often
referred to as ester gums. Additionally, natural resins such as glycerol esters of
partially hydrogenated rosins, glycerol esters of polymerized rosins, glycerol esters
of partially dimerized rosins, glycerol esters of tally oil rosins, pentaerythritol esters
of partially hydrogenated rosins, methyl esters of rosins, partially hydrogenated
methyl esters of rosins and pentaerythritol esters of rosins are typically applied in
chewing gum bases. Other resinous compounds typically applied in chewing gum
bases include synthetic resins such as terpene resins derived from alpha-pinene, beta-
pinene, and/or d-limonene and natural terpene resins.
It is an object of the present invention to avoid the application of natural resin
because of lack of degradability of these components.
The synthetic resin polyvinyl acetate (PVA) is substantially non-degradable in the
environment and thus the use of this resin polymer in gum bases has a high influence
on the non-degradability of chewing gum. PVA is usually added to a gum base in
amounts dependent upon the molecular weight range, and thereby i.e. provides
stretch or elasticity to the gum base. The total amount of PVA used in a gum base

composition is usually from about 5% to 95% by weight based on the total gum base
composition. Typically, the amount of PVA in chewing gum bases is in the range of
10-30%, and thus constitutes a major part of the entire gum base composition. As
this synthetic resin is substantially non-degradable in the environment, this
component in the gum base contributes significantly to the overall non-degradability
of chewing gum based on such gum bases.
It is an object of the invention to create a biodegradable polymer, suited for chewing
gum and with improved degradability.
It is a further object of the present invention to prepare a chewing gum comprising a
polymer, which is particularly degradable and may substitute the resin part of a
chewing gum.
It is a further object of the invention to obtain a chewing gum polymer having
improved biodegradability properties with respect to e.g. degradation process and/or
the degradation residues.
SUMMARY
The invention relates to a chewing gum comprising at least one biodegradable
polymer in an amount of from about 0.1 % to about 95 %, said biodegradable
polymer having a glass transition temperature (Tg) above 37°C.
In an embodiment of the invention a chewing gum comprises at least one
biodegradable polymer in'an amount of from about 0.1 % to about 95 %, said
biodegradable polymer having a glass transition temperature (Tg) above 37°C and
having a molecular weight (Mn) within' the range of approximately 500 to 60000
g/mol and wherein said chewing gum comprises less than approximately 5% by
weight of natural resins.

According to an embodiment of the invention, a high Tg of the low molecular weight
polymer component of the chewing gum, namely the biodegradable component
having a molecular weight (Mn) within the range of approximately 500 to 400000
g/mol, results in an improved effect of the applied low molecular weight polymer. In
other words, according to the invention an improved effect of the low molecular
weight polymer component has been obtained. Such improvement may e.g. result in
the possibility of reducing the overall amount of the low molecular weight polymers
which may be significant with respect to stability. This is in particular the fact when
dealing with biodegradable chewing gum.
According to the invention the amount of natural resins in the final chewing gum
should be kept low due to the fact that the desired biodegradability is compromised
by the nature of the natural resins available.
Moreover, according to an embodiment of the invention, the use of high-Tg
polymers facilitates the use of high-Tg-inducing monomers, which may be regarded
as more biodegradable when dealing with e.g. lactidε-based or glycolidε- based
biodegradable polymers. Thus, degrad'ability of lactonε-polymers is not as fast as
either lactidε- or glycolidε-polymers, and furthermore the degradation products of
lactonε-polymers are less preferred than those of lactide and/or glycolide polymers.
Moreover, the application of high-Tg properties according to the invention facilitates
use of advantageous polymer monomers. According to an advantageous embodiment
of the invention, a biodegradable polymer may be made substantially on the basis of
lactides and/or glycolides alone and/or the content of lactones may be minimized.
According to a preferred embodiment of the invention, the chewing should comprise
less than approximately 2% by weight of natural resins.

In an embodiment of the invention, said chewing gum comprises said at least one
biodegradable polymer in an amount of from about 2 to 60 % by weight.
In an embodiment of the invention, said biodegradable polymer has a glass transition
temperature (Tg) above about 40°C.
In an embodiment of the invention, said chewing gum is substantially free of natural
resins.
According to a preferred embodiment of the invention, use of natural resins should
be avoided in order to obtain a chewing gum, which may be regarded as completely
biodegradable due to the fact that natural resins features very little biodegradability,
if any, compared to typical synthetic polyester-based polymers.
The natural resins, which according to the present invention should be avoided,
include natural rosin esters, often referred to as ester gums including as examples
glycerol esters of partially hydrogenated rosins, glycerol esters of polymerised
rosins, glycerol esters of partially dimerised rosins, glycerol esters of tally oil rosins,
pentaerythritol esters of partially hydrogenated rosins, methyl esters of rosins,
partially hydrogenated methyl esters of rosins, pentaerythritol esters of rosins.
According to an embodiment of the present invention, even those natural resins,
which according to some litterature may have some degradability over very long
periods and at elevated temperatures, are also not acceptable according to the present
invention in any considerable amount.
Other resinous compounds include synthetic resins such as terpene resins derived
from alpha-pinene, beta-pinene, and/or d-limonene, natural terpene resins. Such
resins are not regarded as biodegradable according to the present invention. Thus,

they are not acceptable according to the present invention in any considerable
amount.
It is an object of the present invention to avoid the application of natural resin
because of the marked lack of degradability of these components. According to the
present invention, the biodegradable polymers with a high Tg of at least 37°C has a
larger effect as resinous compounds than biodegradable polymers of lower Tg.
Hence, the biodegradable polymers of high Tg may be excellent substitutes for
natural resins.
In a further embodiment of the invention, the amount of resin substitute in a chewing
gum may be lowered, when applying the effective high-Tg-polymers of the present
invention.
In an embodiment of the invention, said chewing gum comprising said at least one
biodegradable polymer further comprises at least one elastomeric compound.
In an embodiment of the invention, said biodegradable polymer has a plasticizing
effect on said elastomeric compound.
In a preferred embodiment of the invention, the biodegradable polymer with Tg
above 37°C functions as plasticizer for the elastomeric part of the chewing gum. In
other words, according to an embodiment of the invention, the high Tg
biodegradable polymer acts as elastomer plasticizer, which is typically the role of a
resinous compound. The biodegradable chewing gum polymer of the present
invention may therefore be referred to as a biodegradable resin.
In an embodiment of the invention; the total content of polymers, including one or
more biodegradable resins of high Tg and one or more elastomeric compounds, in
the final chewing gum may preferably be in the range of 5 to 90%, preferably in the

range of 20 to 70% by weight of the chewing gum. A polymer content, which is too
low, may result in a chewing gum, which is too soft, which dissolves in the mouth
and is completely swallowed or leaving a water insoluble part, which is too small for
chewing. On the other hand, if the polymer content is too high, the chewing gum
may be extremely hard and/or falling apart. Within the limits of reasonable polymer
content, there are various possibilities of adjusting the texture of a chewing gum
comprising a biodegradable resin of high Tg according to the present invention.
In an embodiment of the invention, said chewing gum comprises said biodegradable
polymer in an amount in the range of 2 to 50 %.
According to the invention, the robustness of the chewing gum may be enhanced by
an increase in the amount of the polymer part of the chewing gum. Specifically
according to the invention, when keeping the elastomer content at a constant level,
while increasing the amount of biodegradable polymer of high Tg according to the
invention, the robustness of the chewing gum may be clearly enhanced.
In an embodiment of the invention, said chewing gum comprises said biodegradable
polymer in an amount in the range of 5 to 40 %, preferably in the range of 10 to 30
%.
It should be noted, that it is important in the manufacture of chewing gum to bring
about a balance between elastomeric and resinous compounds. According to the
present invention, a biodegradable polymer of high Tg, which is above human body
temperature, is suitable as at least one of the resinous polymers in a chewing gum.
The amount of the resinous biodegradable polymer should preferably not encompass
the whole polymer part of the chewing gum. Depending on the actual elastomer used,
the resin content may advantageously be lowered to make room for a higher content
of elastomer, which may improve the texture of the final chewing gum.

In an embodiment of the invention, said chewing gum comprises said biodegradable
polymer in an amount in the range of 5 to 25 %.
According to the invention, the final chewing gum texture may be designed by
adjusting the amount of high-Tg-polymer. The sufficient amount, according to the
present invention, of the biodegradable polymer in a chewing gum may preferably be
considerably lower than the amount, which would be necessary in the case of using a
comparable polymer with a lower Tg.
In an embodiment of the invention, said biodegradable polymer has a glass transition
temperature (Tg) above 38 °C.
In an embodiment of the invention the chewing gum comprises an elastomeric
compound in an amount of at least 0.5 %, preferably at least 1 % by weight of the
chewing gum.
In an embodiment of the invention the chewing gum comprises an elastomeric
compound in an amount of at least 5 %, preferably at least 8 % by weight of the
chewing gum.
In an embodiment of the invention the chewing gum comprises an elastomeric
compound in an amount within the range of about 1% to 40% by weight of the
chewing gum.
According to the present invention, the high-Tg biodegradable polymer may be
considered to hereby have a great strength as a resin compound i.e. an advantageous
plasticizer or solvent for the elastomeric compound in the chewing gum.
In an embodiment of the invention, said biodegradable polymer has a glass transition
temperature (Tg) in the range of 38°C to 90°C.

Previously it was supposed that polymers applied in chewing gum had to have a Tg-
value below human body temperature, because logically Tg would be the limit
between a polymer being glassy or being chewable. Now it has surprisingly been
found, that it is possible to apply a polymer having a Tg-value well above human
body temperature without compromising the chewability of the final chewing gum,
as the polymer may provide the function of a resin, i.e. as a plasticizer for an
elastomer in the chewing gum.
In an embodiment of the invention, said biodegradable polymer has a glass transition
temperature in the range of 41°C to 75°C.
In an embodiment of the invention, said biodegradable polymer has a glass transition
temperature in the range of 42°C to 65°C.
In an embodiment of the invention, said biodegradable polymer has a glass transition
temperature in the range of 43 °C to 48°C.
The present invention relates to a chewing gum comprising biodegradable polymers
having favorable resinous properties and being exceedingly degradable. Furthermore
the degradation products of the inventive biodegradable chewing gum polymers are
notably desirable as they are part of biochemical pathways.
When the Tg of the biodegradable polyester polymer of the invention is a couple of
degrees above mouth temperature, but not more than about ten to twenty degrees
above mouth temperature, an advantageous embodiment of the invention may be
obtained, as the performance as resinous and elastomer plasticizing compound is
high without imparting too hard texture in the final chewing gum.

Moreover, a high robustness may be obtained of the chewing gum comprising the
biodegradable polymer having Tg in this Tg-range.
In an embodiment of the invention, said biodegradable polymer has a molecular
weight (Mn) in the range of 1000 to 40000 g/mol, preferably in the range of 1000 to
25000 g/mol.
According to a preferred embodiment of the invention, a relatively low molecular
weight of the relevant biodegradable polymer is one of the factors leading to a
desirable texture of the final chewing gum. The low molecular weight polymer
should provide the resinous properties, typically a plasticizing effect, which is useful
in combination with elastomeric polymers.
In an embodiment of the invention, said biodegradable polymer has a molecular
weight (Mn) in the range of 3000 to 22000 g/mol, preferably in the range of 3000 to
15000 g/mol.
According to an embodiment of the invention, the plasticizing effect may be
improved, when lowering the molecular weight. A molecular weight somewhat close
to the molecular weight of conventional synthetic resins may be preferred.
In an embodiment of the inventionj said biodegradable polymer is a polyester.
t
In an embodiment of the invention, said biodegradable polyester polymer is
obtainable by ring-opening polymerization of cyclic monomers.
According to an embodiment of thε- invention, an advantageous biodegradable
polyester polymer may be obtained based on cyclic monomers.

In an embodiment of the invention, said cyclic monomers are selected from the
group of cyclic esters and cyclic carbonates.
In an embodiment of the invention, the biodegradable polyester polymer obtained
from cyclic esters and/or cyclic carbonates may provide a chewing gum according to
the invention with preferred properties with regard to texture and degradability.
In an embodiment of the invention, said cyclic monomers are selected from the
group of D,L-lactide, L-lactide, glycolide, s-caprolactone, δ-valerolactone,
trimethylene carbonate (TMC) and dioxanone.
In an embodiment of the invention, at least one of said cyclic monomers is a high-
Tg-inducing monomer.
In the present text the terms "high-Tg-inducing monomer" and "low-Tg-inducing
monomer" refer to monomers, which when polymerized alone or in their respective
groups result in polymers of high- and low Tg, respectively. Herein the resulting
polymers of high- and low-Tg may be understood as polymers having a molecular
weight of at least 500 Mn. In other words, the terms high- and low-Tg-inducing
monomers are used for monomers, which, when polymerized to polymers of at least
500 Mn, may preferably lead to either high or low Tg of the polymer. Herein a high
Tg is defined as a Tg above mouth temperature and a low Tg is correspondingly
defined as a Tg below mouth temperature.
The chewing gum elastomer plasticizer polymer, also referred to as biodegradable
resin according to the present invention may sometimes in the present text be
referred to as 'polyester resin' when it is intended to refer to the polymer as being a
polyester with resin-like properties. •':.

In an embodiment of the invention the polyester resin comprises monomer units
originating from one or more sorts of high-Tg-inducing monomers such as lactide or
glycolide forming a homo-polymer or a co-polymer with high Tg.
In an embodiment of the invention, the high-Tg-inducing monomers may be chosen
among D,L-lactide, L-lactide, and glycolide.
The observed and desired effect of applying at least one high-Tg-inducing monomer
may be to obtain a chewing gum polymer, which is harder and less elastic than usual
chewing gum polymers. Such polymer has been observed to imply a pleasing texture
in the final chewing gum.
In an embodiment of the invention, said polyester is a polymer obtainable by the
polymerization of one single type of high-Tg-inducing monomers.
In an embodiment of the invention, the biodegradable polyester polymer is a homo-
polymer based on one type of high-Tg-inducing monomers only. Preferred polymers
of this type may be poly(lactide) or poly(glycolide).
In an embodiment of the invention, said polyester is a copolymer obtainable by the
polymerization of at least two different high-Tg-inducing monomers.
In an embodiment of the invention,' a co-polymer such as a poly(d,l-lactidε-co-
glycolide) may be applied as the high-Tg-biodegradable polymer in a chewing gum
according to the present invention. A purpose of introducing a co-polymer may be
that such co-polymer may be more amorphous and less crystalline than a homo-
polymer, and that these features may contribute further to the advantageous texture
properties of the final chewing gum.

In an embodiment of the invention, said polyester is a copolymer obtainable by the
polymerization of at least one low-Tg-inducing monomer with at least one high-Tg-
inducing monomer.
In an embodiment of the invention a small percentage of low-Tg-inducing monomers
is introduced in the polymer chain to control the Tg of the resulting copolymer.
While keeping the Tg above 38 °C according to the present invention, the texture of
the polymer may according to a preferred embodiment of the invention be adjusted
by regulating the percentage of low-Tg-inducing monomers in the copolymer.
In an embodiment of the invention, a high Tg of the biodegradable resin polymer has
improved effect as resinous compound, thereby lowering the necessary amount of
resin in order to plasticize the elastomer part of the chewing gum.
In an embodiment of the invention, the structure of the high-Tg-biodegradable
polymer may be tuned by the balance between high- and low-Tg-inducing monomers
in the co-polymer to provide a polymer with elastoplastic and considerably amorph
properties. Hereby, a preferred quality of the final chewing gum according to the
invention may be achieved.
A polymer having elastoplastic properties may comprise both elastomeric and
resinous properties and act as elastomer at lower temperatures and as resin
(elastomer plasticizer) at higher temperatures.
In an embodiment of the invention,- the molar ratio of the at least one high-Tg-
inducing monomer to the at least one low-Tg-inducing monomer is in the range of
75/25 to 99/1, preferably in the range of 85/15 to 99/1.
An advantage of such ratio between low and high Tg-inducing monomers is that
improved elastoplastic features may be obtained.

In an embodiment of the invention, the molar ratio of the at least one high-Tg-
inducing monomer to the at least one low-Tg-inducing monomer is in the range of
90/10 to 99/1, preferably in the range of 95/5 to 99/1.
In an embodiment of the invention, the molar ratio of the at least one high-Tg-
inducing monomer to the at least one low-Tg-inducing monomer is in the range of
95/5 to 98/2.
In an embodiment of the invention, said at least one high-Tg-inducing monomer is
selected from the group of monomers comprising D,L-lactide, L-lactide and
glycolide.
When these monomer units constitute a relatively large part of the polymer an
advantage may be obtained with regard to the degradation products. When the goal is
to obtain a biodegradable chewing gum, it may provide a significant contribution to
the usefulness of the chewing gum that the monomer- or oligomer-degradation
products are desirable in the environment. This is what may be obtained by the
present invention, as the fraction of lactic acid, glycolic acid etc. as degradation
products may be increased compared to the degradation products of prior art
biodegradable chewing gum polymers, wherein low-Tg-inducing monomers such as
e.g. lactones are often used in higher percentages.
The application of these high-Tg-inducing monomers in the biodegradable resin in
the chewing gum of the present invention generally involves some important
advantages as regards fast rate of degradability with favorable and non-toxic
degradation products. In addition hereto, these monomer compounds may be
purchased at low cost

By increasing the percentage of high-Tg-inducing monomers in the polymer, the Tg
of the resulting polymer is raised, and experiments have shown that it is actually
possible to obtain desired chewing gum characteristics, when applying such hard and
inelastic polymers in chewing gum in combination with an elastomeric compound.
In an embodiment of the invention, said at least one low-Tg-inducing monomer is
selected from the group of monomers comprising s-caprolactone, δ-valerolactone,
trimethylene carbonate (TMC) and dioxanone.
As regards polymers made at least partly from these monomers, they may represent
some ambiguity with regard to degradation rate. Certainly, they degrade with a much
more rapid rate than conventional chewing gum polymers such as PVA or natural
resins. However, when compared to high-Tg-polymers such as poly(d,l-lactide), they
may be observed to degrade at a slower rate. Hence, when taking degradability
aspects into account, the amount of high-Tg-inducing monomers may
advantageously be increased.
In an embodiment of the invention, ε-caprolactone may be preferred over δ-
valerolactone because of cost considerations.
In an embodiment of the invention; said ring-opening polymerization is initiated by
one or more initiators.
In an embodiment of the invention, said initiators comprise about 0.01 to 1.0 % by
weight of said biodegradable polyester polymer.
In an embodiment of the ihvention at least 50 mol %, preferably at least 70 mol % of
said initiators are difunctional.

In an embodiment of the invention, the mol percentage of difunctional initiators may
be used to control the linearity of the biodegradable polymer. If both difunctional and
higher functional initiators are used, an increase in the mol percentage of difunctional
initiators may increase the linearity, while an increase in the higher functional
initiators may induce more branching in the polymer.
In an embodiment of the invention, an advantageous robustness and texture of the
chewing gum may be obtained, when the relatively low molecular weight
biodegradable polyester polymer of high Tg obtains a high degree of linearity and
crystallinity. Excellent properties as biodegradable resin in the chewing gum may
hereby be obtained.
Thus, the excellent resinous properties may be derived from the fact that especially a
biodegradable polymer with glass transition temperature above mouth temperature
may gain fine elastomer plasticizing properties, when somewhat crystalline and
linear regions are introduced therein.
In an embodiment of the invention, a preferred group of difunctional initiators may
be diol initiators such as e.g. 1,2 -propane diol.
In an embodiment of the invention, said polyester polymer is substantially linear.
In an embodiment of the invention, a high linearity may be associated with an
improved elastomer plasticizing function of the high-Tg-biodegradable polymer.
Furthermore, a higher linearity may also imply a higher crystallinity, which in an
embodiment of the invention may entail that a smaller amount of biodegradable resin
polymer is needed in order to obtahvthe desired texture of the final chewing gum
according to the present invention.

In an embodiment of the invention, said substantially linear polyester polymer
comprises above 50 percent linear polymer chains.
Accordingly, in an embodiment of the invention, a high percentage linearity of the
biodegradable polymer of the invention, may contribute to a high robustness and
pleasant texture of the chewing gum.
In an embodiment of the invention, said substantially linear polyester polymer
comprises above 70 percent linear polymer chains.
In an embodiment of the invention, said substantially linear polyester polymer
comprises above 80 percent linear polymer chains.
Hereby, in an embodiment of the invention, a further improvement may be obtained
with regard to elastomer plasticizer function of the high-Tg biodegradable polyester
polymer.
In an embodiment of the invention, said biodegradable polyester polymer is
obtainable by condensation polymerization of polyfunctional acids or derivatives
thereof and/or polyfunctional alcohols or derivatives thereof.
Examples of poly condensation methods of producing polymers from carboxylic
acids have been disclosed in US 5,310,865 and US 4,273,920.
In an embodiment of the invention, said polyfunctional acids are selected from the
group of lactic acids and glycolic acids.
In an embodiment of the invention, said polyfunctional acids are
polyhydroxycarboxylic acids or hydroxycarboxylic acids.

In an embodiment of the invention, said chewing gum comprises an elastomeric
compound in an amount of at least 5 %, preferably at least 10 % by weight of the
chewing gum.
The amount of elastomeric compound depends on the actually applied elastomer and
resin. It has been found that a nice texture of the chewing gum according to the
invention may be obtained, when the high-Tg biodegradable resin is combined with
an elastomeric compound in a gum base, which is introduced into a standard chewing
gum formulation.
In an embodiment of the invention, said at least one elastomeric compound is a
biodegradable elastomer.
In order to obtain a highly degradable chewing gum, it may be preferred that both the
resinous and the elastomeric parts of the chewing gum are biodegradable.
In an embodiment of the invention, said biodegradable elastomer is obtainable by the
polymerization of at least' one alcohol or derivative thereof and at least one
carboxylic acid or derivative thereof.
Useful elastomers of this kind may be prepared from a large number of different
monomers.
In an embodiment of the invention an advantageous elastomer polymer may be
prepared from dimethyl terephthalate, dimethyl adipate, and di(ethylene glycol).
Further examples within the scope of the invention include polymers, which may
generally be prepared by step-growth polymerization of di-, tri- or higher-functional
alcohols or esters thereof with di-, tri- or higher-functional aliphatic or aromatic
carboxylic acids or esters thereof. Likewise, also hydroxy acids or anhydrides and
halides of polyfunctional carboxylic acids may be used as monomers. The

polymerization may involve direct polyesterification or transesterification and may
be catalyzed.
In another embodiment, useful elastomer compounds may include polyester
polymers obtained by the polymerization of one or more cyclic esters such as lactide,
glycolide, trimethylene carbonate, δ-valerolactone, β-propiolactone and ε-
caprolactone.
Regardless of the monomer composition, the molecular weight of the elastomeric
compound may be considerably higher than the molecular weight of the resinous
high-Tg biodegradable polymer according to the present invention. Likewise, the
glass transition temperature may be much lower for the elastomer.
In an embodiment of the invention, the water content is less than 3 %, preferably less
than 1.5 %, and most preferably less than 1 % by weight of the chewing gum.
In some of the most preferred embodiments of the present invention, a low water
content in the final chewing gum is of great importance because of the chewing gum
content of highly degradable polymers such as poly(lactide). When applying such
polymers being particularly susceptible to hydrolytical degradation, a low water
content may according to the present invention be a crucial factor to avoid or at least
minimize prε-chewing degradation, which is very undesired in the chewing gum.
Keeping the water content in the chewing gum low may increase the keeping
qualities of the final chewing gum product considerably, and the period of storage
before use may be prolonged without compromising the chewing gum taste,
appearance and quality.
Thus, due to the large content of particularly degradable polymers in the chewing
gum of the present invention, it is a general goal to keep to water content as low as
possible.

The chewing gum of the present invention may be manufactured by several different
processes such as a batch process, by extrusion, by a onε-step process, etc..
The shape of the resulting chewing gum tablet may be any manufacturable
geometrical shape, such as round, oval, flattened, stick, etc. The tablet may also be
multi-modular, e.g. center-filled.
The chewing gum according to the invention may also be made by means of
compression, as a compressed multi-modular table, etc.
In an embodiment of the invention, said chewing gum comprises one or more
chewing gum ingredients selected from the group comprising flavoring agents,
sweetening agents, fillers, softeners, emulsifiers, and active ingredients.
In an embodiment of the invention, said flavoring agents comprise natural and
synthetic flavorings in the form of natural vegetable components, essential oils,
essences, extracts, powders, including acids and other substances capable of affecting
the taste profile.
In an embodiment of the invention, said chewing gum comprises flavor in an amount
of 0.01 to about 25 wt %, preferably in an amount of 0.1 to about 5 wt %, said
percentage being based on the total weight of the chewing gum.
In an embodiment of the invention, the chewing gum comprises at least one softener
in an amount of about 0 to about 20 % by weight of the chewing gum, more typically
about 0 to about 10 % by weight of the chewing gum.
According to the present invention, it has been found that softener may
advantageously be added to the chewing gum of the present invention in an amount

corresponding to the amount used in conventional chewing gum. According to the
present invention, a satisfactory texture of a chewing gum comprising a resinous
compound of high Tg may be obtained, even when the amount of added softener is
rather low, that is below 10 % or even below 5 % by weight of the chewing gum.
In an embodiment of the invention, the softeners may be selected among tallow,
hydrogenated tallow, hydrogenated and partially hydrogenated vegetable oils, cocoa
butter, glycerol monostearate, glycerol triacetate, lecithin, mono-, di- and
triglycerides, acetylated mono- or diglycerides, fatty acids - such as stearic, palmitic,
oleic and linoleic acids, waxes, PGE and mixtures thereof.
In an embodiment of the invention, the amount of emulsifier is in the range of 0 to 18
% by weight of the chewing gum.
In different embodiments of the present invention, the chewing gum may be provided
either with or without emulsifier.
In an embodiment of the invention, said sweetening agents are selected from the
group comprising bulk sweeteners, and high intensity sweeteners, and combinations
thereof.
In an embodiment of the invention, thechewing gum comprises sugar.
In an embodiment of the invention, the chewing gum is sugar free.
In an embodiment of the invention, said bulk sweeteners comprises an amount of
about 5 to about 95%, preferably about 20 to about 80% by weight of the chewing
gum.

According to the invention, the bulk sweeteners may be sugar sweeteners, non-sugar
sweeteners and combinations thereof.
In an embodiment of the invention, the sugar sweeteners may comprise saccharidε-
containing compounds such as sucrose, dextrose, maltose, dextrins, trehalose, D-
tagatose, dried invert sugar, fructose, levulose, galactose, corn syrup solids, alone or
in combination.
Moreover, in an embodiment of the invention, the non-sugar sweeteners may
comprise sugar alcohols such as sorbitol, mannitol, xylitol, hydrogenated starch
hydrolysates, maltitol, isomaltol, erythritol, lactitol, alone or in combination.
In an embodiment of the invention, the chewing gum comprises high intensity
sweeteners in an amount of about 6 to about 1.2 %, preferably about 0.1 to about 0.6
% by weight of the chewing gum.
In an embodiment of the invention, the high intensity sweeteners may comprise
sucralose, aspartame, salts of acesulfame, alitame, neotame, twinsweet, saccharin and
its salts, cyclamic acid and its salts, glycyrrhizin, dihydrochalcones, thaumatin,
monellin, stevioside, alone or in combination.
In an embodiment of the invention, the chewing gum comprises filler in an amount
of about 0 to about 50% by weight' of the chewing gum, more typically about 10 to
about 40% by weight of the chewing gum:
In an embodiment of the invention, the chewing gum comprises at least one coloring
agent.
In an embodiment of the invention, said chewing gum ingredients comprise active
ingredients.

In an embodiment of the invention, the active ingredients may be selected among
medicines, oral compositions, anti-smoking agents, highly potent sweeteners, pH
adjusting agents, nutritients, antiseptics, minerals, agents for care or treatment of the
oral cavity and the teeth, dietary supplements, other active ingredients and
combinations thereof.
In an embodiment of the invention, said chewing gum is coated with an outer coating
selected from the group comprising hard coating, soft coating and edible film-
coating.
The outer coating may be a sugar coating or a sugarless coating or a combination
thereof.
In an embodiment of the invention, the outer coating is a hard coating comprising at
least 50 % by weight of a polyol selected from the group comprising sorbitol,
maltitol, mannitol, xylitol, erythritol, lactitol and isomalt.
In a further embodiment of the invention, the edible film-coating comprises at least
one component selected from the group comprising wax and an edible film-forming
agent such as a cellulose derivative, a modified starch, a dextrin, gelatine, shellac,
gum arabic, zein, a vegetable gum, a synthetic polymer and any combination thereof.
In an embodiment of the invention, the outer coating comprises at least one additive
component selected from the group comprising a binding agent, a moisture absorbing
component, a film forming agent, a dispersing agent, an antisticking component, a
bulking agent, a flavoring agent, a coloring agent, a pharmaceutically or cosmetically
active component, a lipid component, a wax component, a sugar, an acid and an
agent capable of accelerating the after-chewing degradation of the degradable
polymers.

In an embodiment of the invention, the agent capable of accelerating after-chewing
degradation of the degradable polymers may be one or more enzymes selected
among those mentioned in PCT/DK2003/000939.
DETAILED DESCRIPTION
According to a preferred definition of biodegradability according to the invention,
biodegradability is a property of certain organic molecules whereby, when exposed
to the natural environment or placed within a living organism, they react through an
enzymatic or microbial process, often in combination with a chemical process such
as hydrolysis, to form simpler compounds, and ultimately carbon dioxide, nitrogen
oxides, methane, water and the like.
In the present context the term 'biodegradable polymers' means environmentally or
biologically degradable polymer compounds and refers to chewing gum base
components which, after dumping the chewing gum, are capable of undergoing a
physical, chemical and/or biological degradation, whereby the dumped chewing gum
waste becomes more readily removable from the site of dumping or is eventually
disintegrated to lumps or particles, which are no longer recognizable as being
chewing gum remnants. The degradation or disintegration of such degradable poly-
mers may be effected or induced by physical factors such as temperature, light,
moisture, etc., by chemical factors such as oxidative conditions, pH, hydrolysis, etc.
or by biological factors such as microorganisms and/or enzymes. The degradation
products may be larger oligomers, trimers, dimers and monomers.
Preferably, the ultimate degradation products are small inorganic compounds such as
carbon dioxide, nitrogen oxides, methane, ammonia, water, etc.
As referred to herein, the glass transition temperature (Tg) is be determined by for
example DSC (DSC: differential scanning calorimetry). The DSC may generally be

applied for determining and studying of the thermal transitions of a polymer and
specifically, the technique may be applied for the determination of a second order
transition of a material. The transition at Tg is regarded as such a second order
transition, i.e. a thermal transition that involves a change in heat capacity, but does
not have a latent heat. Hence, DSC may be applied for studying Tg. Unless otherwise
stated the heating rate used is 10°C/min throughout the application.
Unless otherwise indicated, as used herein with regard to polymers, the term
"molecular weight" means number average molecular weight (Ma) in g/mol.
Furthermore, as used herein the short form PD designates the polydispersity of
polymers, polydispersity being defined as Mw /Mn, where Mw is the weight average
molecular weight of a polymer. A well-established technique for characterization of
biodegradable polymers is gel permeation chromatography (GPC).
In the present text, it is assumed that the temperature in the mouth of the chewing
gum consumer is about human body temperature, although it may in praxis during
chewing be a few degrees below'body temperature. A glass transition temperature
above mouth temperature is herein referred to as a high Tg, whereas a Tg below
mouth temperature is herein referred to as a low Tg.
Chewing gum of the present invention typically comprises a water-soluble bulk
portion, a water-insoluble chewable gum base portion and flavoring agents. The
water-soluble portion dissipates with a portion of the flavoring agent over a period of
time during chewing. The gum base portion is retained in the mouth throughout the
chew. The term chewing gum refers to both a chewing and bubble type gum in its
general sense.
The gum base is the masticatory substance of the chewing gum, which imparts the
chew characteristics to the final product. The gum base typically defines the release
profile of flavors and sweeteners and plays a significant role in the gum product.

The insoluble portion of the gum typically may contain any combination of
elastomers, vinyl polymers, elastomer plasticizers, waxes, softeners, fillers and other
optional ingredients such as colorants and antioxidants.
The composition of gum base formulations can vary substantially depending on the
particular product to be prepared and on the desired masticatory and other sensory
characteristics of the final product However, typical ranges (% by weight) of the
above gum base components are: 5 to 80% by weight elastomeric compounds, 5 to
80% by weight elastomer plasticizers, 0 to 40% by weight of waxes, 5 to 35% by
weight softener, 0 to 50% by weight filler, and 0 to 5% by weight of miscellaneous
ingredients such as antioxidants, colorants, etc. The gum base may comprise about 5
to about 95 percent, by weight, of the chewing gum, more commonly, the gum base
comprises 10 to about 60 percent of the gum.
Elastomers provide the rubbery, cohesive nature to the gum, which varies depending
on this ingredient's chemical structure and how it may be compounded with other
ingredients. Elastomers suitable for use in the gum base and gum of the present
invention may include natural or synthetic types.
Elastomer plasticizers vary the firmness of the gum base. Their specificity on
elastomer inter-molecular chain breaking (plasticizing) along with their varying
softening points cause varying degrees' of finished gum firmness and compatibility
when used in base. This may be important when one wants to provide more
elastomeric chain exposure to the'alkanic chains of the waxes.
The elastomer compounds may be of natural origin but are preferably of synthetic
origin, preferably synthetic polyesters: According to the invention, the resin
compounds are preferably biodegradable polymers, and in preferred embodiments,

the resin compounds are biodegradable synthetic polyesters. Natural resins of any
kind are avoided in the chewing gum of the present invention.
According to the present invention, the chewing gum comprises at least one
biodegradable polymer having a high Tg being above 37°C. Furthermore, according
to the present invention, these biodegradable polymers are very suitable as resinous
compounds in the chewing gum of the present invention. Here below a series of
examples of monomer compositions are given, which in tuned molar ratios may be
applied for the high-Tg biodegradable polymer, which is part of the chewing gum of
the present invention.
According to different embodiments of the invention, a high-Tg biodegradable
polymer may comprise at least one of the high-Tg-inducing monomers chosen
among lactides or glycolides and possibly one or more low-Tg-inducing monomers
chosen among lactones and cyclic carbpnates.
The lactone monomers ■ may be selected from the group of δ-caprolactone, δ-
valerolactone, y-butyrolactbne, and β-propiolactone, also including s-caprolactones,
5-valerolactones, y-butyrolactones, or p-propiolactones that have been substituted
with one or more alkyl or aryl substituents at any non-carbonyl carbon atoms along
the ring. The carbonate monomers may be chosen from the group of trimethylene
carbonate, 5-alkyl-l,3-dioxan-2-one,' •5,5-dialkyl-l53-dioxan-2-one, or 5-alkyl-5-
alkyloxycarbonyl-l,3-dioxan-2-one,' ethylene carbonate, 3-ethyl-3-hydroxymethyl,
propylene carbonate, trimethylolpropane monocarbonate, 4, 6dimethyl-l, 3-
propylene carbonate, 2,2-dimethyl trimethylene carbonate, and 1,3-dioxepan-2-one.
According to the present invention, some preferred monomers are cyclic monomers
such as D,L-lactide, L-lactide, and'glycolide, which are high-Tg-inducing, and ε-
caprolactone, 5-valerolactone, trimethylene carbonate (TMC) and dioxanone, which
are low-Tg-inducing.

In order to obtain the desired high Tg, either homo-polymers or co-polymers of high-
Tg-inducing monomers alone are used, or a combination of high- and low-Tg
inducing monomers are used, wherein it is important that the ratio between high-Tg
inducing monomers and low-Tg inducing monomers is controlled.
According to an embodiment of the invention, some examples of homo-polymers or
co-polymers of high-Tg-inducing monomers may include the following: poly(L-
lactide); poly(D-lactide); poly(D, L-lactide); poly(mesoIactide); poly(glycolide);
poly(L-lactidε-co-D, L-lactide); poly(L-lactidε-co-meso-lactide); poly(L-lactidε-co-
glycolide); poly(D, L-lactidε-co-meso-lactide); poly(D, L-lactidε-co-glycolide);
poly(mesolactidε-co-glycolide), etc..
According to a further embodiment of the invention, one or more high-Tg-inducing
monomers and one or more low-Tg-inducing monomers may be polymerized
together, the molar ratio of high/low being in the range of 75/25 to 99/1, preferably
in the range of 85/15 to 99/1, and typically in the range of 95/5 to 99/1. In other
words, the mol percentage of high-Tg-inducing monomers is at least 75%, preferably
at least 85%, and typically at least 95% of the total mol number of monomers
forming the resulting polymer. While maintaining these ratios, preferred
combinations of cyclic monomers may include the following:
D,L-lactide/ε-eaprolactone,
D,L-lactide/TMC '.'■■•.:
D,L-lactide/5-valerolactone
D,L-lactide/dioxanone
D,L-lactide in combination with any tvto3 three, or four low Tg-inducing monomers
L-lactide/s-caprolactone
L-Iactide/TMC

L-lactide/5-valerolactone
L-lactide/dioxanone
L-lactide in combination with any two, three, or four low Tg-inducing monomers
D,L-lactide/glycolide/s-caprolactone
D,L-lactide/glycolide/TMC
D,L-lactide/glycolide/δ-valeroIactone .
D,L-lactide/glycolide/dioxanone
D,L-lactide/glycolide in combination with any two, three, or four low Tg-inducing
monomers
L-iactide/glycolide/s-caprolactone
L-lactide/glycolide/TMC
L-lactide/glycolide/5-valerolactone
L-Iactide/glycoIide/dioxanone
L-lactide/glycolide in combination with any two, three, or four low Tg-inducing
monomers
glycolide/ε-caprolactone
glycolide/TMC
glycolide/δ-valerolactone
glycolide/dioxanone
glycolide in combination with any two, three, or four low Tg-inducing monomers
D,L-lactide/L-lactide/s-capr6lactone
D,L-lactide/L-lacride/TMC
D,L-Iactide/L-Iactide/δ-valerolactone
D,L-lactide/L-lactide/dioxanone
D,L-lactide/L-lactide in combination with any two, three, or four low Tg-inducing
monomers

D,L-lactide/L-lactide/glycolide/£-caprolactone
D5L-Iactide/L-Iactide/gIycolide/IMC
D,L-lactide/L-lactide/glycolide/δ-valerolactone
D,L-lactide/L-lactide/glycolide/dioxanone
D,L-lactide/L-laetide/glycolide in combination with any two, three, or four low Tg-
inducing monomers
The polymerization of monomers according to the above compositions may
according to the invention lead to some very degradable high-Tg polymers, which
are suitable as resinous compounds in the chewing gum of the present invention.
A few examples of the resulting high-Tg biodegradable polymers may include
poly (L-lactidε-co-trimethylenecarbonate); poly (L-lactidε-co-epsilon-caprolactone);
poly (D, L-lactidε-co-trimethylenecarbonate); poly (D, L-lactidε-co-epsilon-
caprolactone); poly (meso-lactidε-co-trimethylenecarbonate); poly (mesolactidε-co-
epsilon-caprolactone); poly (glycolidε-cotrimethylenecarbonate); poly (glycolidε-co-
epsilon-caprolactone), etc..
According to an embodiment of the invention, the polymerization process to obtain
the biodegradable polymer, which is applied in the chewing gum of the present
invention, may be initiated by an initiator-such as a polyfunctional alcohol, amine or
other molecules or compounds with multiple hydroxyl or other reactive groups or
mixtures thereof.
According to an embodiment of the invention, examples of suitable multifunctional
initiators include but arε-not limited to glycerol, trimethylolpropane, pentaerythritol,
dipentaerythritol, and ethoxylated or propoxylated polyamines.

Furthermore, in a preferred embodiment of the invention, the initiator may be di-
functional, and examples of applicable di-functional initiators include di-functional
alcohols, and non-limiting examples'include 1,2-propane diol, 1,3-butane diol, other
alkane diols, ethylene glycol, generally alcohols having two hydroxyl groups, and
other di-functional compounds capable of initiating a ring-opening polymerization.
Furthermore, according to the invention, the initiator may comprise in the range of
0.01 to 1.0, preferably 0.05 to 0.8 weight % of the high-Tg biodegradable polyester
polymer, which may be applied in the chewing gum of the present invention.
According to an embodiment of the invention, the fraction of initiators in the biode-
gradable polymer being difunctional or higher functional may be regulated, whereby
the degree of linearity and branching may be controlled.
In an embodiment of the invention, the difunctional initiators comprise at least 50
mol % of the total content of initiator molecules applied. Hereby, a considerable
linearity may be introduced in thε-biodegradable polymer according to the present
invention, and a certain desired' crystallinity may be obtained. Hereby, the
biodegradable polyester polymer may gain very suitable properties as elastomer
plasticizer, and hence an advantageous biodegradable resin may be provided in the
chewing gum of the present invention. To increase the linearity to improve the
crystallinity, plasticizing properties and robustness of the chewing gum in an
embodiment of the invention, the content of difunctional initiators may be raised to
e.g. 60%, 70%, 80%, '90%; or about 100% of the total content of moles initiator
molecules applied.
Accordingly, a substantially linear polyester polymer may according to an embodi-
ment of the invention comprise above e.g. 50 or 80 percent linear polymer chains.

The biodegradable bigh-Tg resinous polymers of the present invention are preferably
obtainable by ring-opening polymerization. However, the method of production is
not limiting for the scope of the present invention. As an example, ring-opening
polymerization of lactide is more commonly used as production method than
polycondensatibn of lactic acid (e.g. a-hydroxypropionic acid). This, however, is
mainly a matter of process conditions and ease of production. As concerns the
resulting polymers, they may be provided with substantially the same composition
and properties and being equally applicable in chewing gum according to the present
invention. The naming of such polymers is often regarded inter-changeable, thus the
names poly(lactide) and poly (lactic acid) may be used for the same polymer.
Generally, the biodegradable polymers used in the chewing gum of the present
invention may be homopolymers, copolymers or terpolymers, including graft- and
block-polymers.
Useful polymers, which may be applied as elastomers in the chewing gum of the
present invention, may generally be prepared by step-growth polymerization of di-,
tri- or higher-functional alcohols or esters thereof with di-, tri- or higher-functional
aliphatic or aromatic carboxylic acids or esters thereof. Likewise, also hydroxy acids
or anhydrides and halides of polyfunctional carboxylic acids may be used as
monomers. The polymerization may involve direct polyesterification or
transesterification and may be catalyzed.
Because polyfunctional carboxylic acids in general are high-melting solids that have
very limited solubility in the polycondensation reaction medium, esters or anhydrides
of the polyfunctional carboxylic acids are often used to overcome this limitation.
Furthermore, polycondensations involving carboxylic acids or anhydrides produce
water as the condensate, which requires high temperatures to be driven off. Thus,
polycondensations involving transesterification of the ester of a polyfunctional acid
are often the preferred process. For example, the dimethyl ester of terephthalic acid

may be used instead of terephthalic acid itself. In this case, methanol rather than
water is condensed, and the former can be driven off more easily than water. Usually,
the reaction is carried out in the bulk (no solvent) and high temperatures and vacuum
are used to remove the by-product and drive the reaction to completion.
Specific examples of aliphatic polyfunctional carboxylic acids, which may be useful
in the preparation of an elastomer applied in the chewing gum of the present
invention, include oxalic, malonic, citric, succinic, malic, tartaric, fumaric, maleic,
glutaric, glutamic, adipic, glucaric, pimelic, suberic, azelaic, sebacic, dodecanedioic
acid, etc. Likewise, specific examples of aromatic polyfunctional carboxylic acids
may be terephthalic, isophthalic, phthalic, trimellitic, pyromellitic and naphthalene
1,4-, 2,3-, 2,6-dicarboxylic acids and the like.
For the purpose of illustration and not limitation, some examples of carboxylic acid
derivatives, which may be used for preparation of the elastomer used in the chewing
gum of the present invention, include hydroxy acids such as 3-hydroxy propionic
acid and 6-hydroxycaproicacid and anhydrides, halides or esters of acids, for
example dimethyl or diethyl esters, corresponding to the already mentioned acids,
which means esters such as dimethyl or diethyl oxalate, malonate, succinate,
fumarate, maleate, glutarate, adipate, pimelate, suberate, azelate, sebacate,
dodecanedioate, terephthalate, isophthalate, phthalate, etc. Generally speaking,
methyl esters are sometimes more preferred than ethyl esters due to the fact that
higher boiling alcohols are more difficult to remove than lower boiling alcohols.
The usually preferred polyfunctional alcohols contain 2 to 100 carbon atoms as for
instance polyglycols and polyglycerols. •
In the polymerization of an: elastomer for usε-in the chewing gum of the present
invention, some applicable examples of alcohpls, which may be employed as such or
as derivatives thereof, include polyols such as ethylene glycol, 1,2-propanediol, 1,3-
propanediol, 1,3-butanediol, 1,4-butanedioI, 1,6-hexanediol, diethylene glycol, 1,4-

cyclohexanediol, 1,4-cyclohexanedimethanol, neopentyl glycol, glycerol,
trimethylolpropane, pentaerythritol, sorbitol, mannitol, etc.
Generally, the elastomer polymers used in the chewing gum of the present invention
may be homopolymers, copolymers or terpolymers, including graft- and block-
polymers.
Further suitable examples of additional environmentally or biologically degradable
chewing gum base polymers, which may be applied in accordance with the gum base
of the present invention, include degradable polyesters, polycarbonates, polyester
amides, polypeptides, homopolymers of amino acids such as polylysine, and proteins
including derivatives hereof such as e.g. protein hydrolysates including a zein
hydrolysate.
In accordance with the general principles in manufacturing a chewing gum within the
scope of the invention, variations of different suitable ingredients are listed and
explained below.
The chewing gum according to the invention may comprise coloring agents.
According to an embodiment of the invention, the chewing gum may comprise color
agents and whiteners such as FD&C-type dyes and lakes, fruit and vegetable
extracts, titanium dioxide and combinations thereof.
Further useful chewing gum base components include antioxidants, e.g. butylated
hydroxytoluene (BHT), butyl hydroxyanisol (BHA), propylgallate and tocopherols,
and preservatives.
In an embodiment of the invention, the chewing gum comprises softeners in an
amount of about 0 to about 18% by weight of the chewing gum, more typically about
0 to about 12% by weight of the chewing gum.

Softeners/emulsifiers may according to the invention be added both in the chewing
gum and the gum base.
A gum base formulation may, in accordance with the present invention, comprise
one or more softening agents e.g. sucrose esters including those disclosed in
WO 00/25598, which is incorporated herein by reference, tallow, hydrogenated
tallow, hydrogenated and partially hydrogenated vegetable oils, cocoa butter,
degreased cocoa powder, glycerol monostearate, glyceryl triacetate, lecithin, mono-,
di- and triglycerides, acetylated monoglycerides, fatty acids (e.g. stearic, palmitic,
oleic and linoleic acids) and combinations thereof. As used herein the term "softener"
designates an ingredient, which softens the gum base or chewing gum formulation
and encompasses waxes, fats, oils, emulsifiers, surfactants and solubilisers.
To soften the gum base further and to provide it with water-binding properties, which
confer to the gum base a pleasant smooth surface and reduce its adhesive properties,
one or more emulsifiers is/are usually added to the composition, typically in an
amount of 0 to 18% by weight, preferably 0 to 12% by weight of the gum base.
Mono- and diglycerides of edible fatty acids, lactic acid esters and acetic acid esters
of mono- and diglycerides of edible fatty acids, acetylated mono and diglycerides,
sugar esters of edible fatty acids, Na-, K-, Mg- and Ca-stearates, lecithin,
hydroxylated lecithin and the like are examples of conventionally used emulsifiers
which can be added to the chewing gum base. In case of the presence of a
biologically or pharmaceutically active ingredient as defined below, the formulation
may comprise certain specific emulsifiers'and/or solubilisers in order to disperse and
release the active ingredient.
Waxes and fats are conventionally used for the adjustment of the consistency and for
softening of the chewing gum base when preparing chewing gum bases. In
connection with the present invention, any conventionally used and suitable type of

wax and fat may be used, such as for instance rice bran wax, polyethylene wax,
petroleum wax (refined paraffin and microcrystalline wax), paraffin, beeswax,
carnauba wax, candelilla wax, cocoa butter, degreased cocoa powder and any
suitable oil or fat, as e.g. .completely or partially hydrogenated vegetable oils or
completely or partially hydrogenated animal fats.
In an embodiment of the invention, the chewing gum comprises filler.
A chewing gum base formulation may, if desired, include one or more
fillers/texturisers including as examples, magnesium and calcium carbonate, sodium
sulphate, ground limestone, silicate compounds such as magnesium and aluminum
silicate, kaolin and clay, aluminum oxide, silicium oxide, talc, titanium oxide,
mono-, di- and tri-calcium phosphates, cellulose polymers, such as wood, and
combinations thereof.
In an embodiment of the invention* the chewing gum comprises filler in an amount
of about 0 to about 50% by weight of the chewing gum, more typically about 10 to
about 40% by weight of the chewing-gum'.
In addition to a water insoluble gum base portion, a typical chewing gum includes a
water soluble bulk portion and one or more flavoring agents. The water-soluble
portion may include bulk sweeteners, high intensity sweeteners, flavoring agents,
softeners, emulsifiers, colors, acidiilants, fillers, antioxidants, and other components
that provide desired attributes:
Suitable bulk sweeteners include both sugar and non-sugar sweetening components.
Bulk sweeteners typically constitute from about 5 to about 95% by weight of the
chewing gum, more typically about 20 to about 80% by weight such as 30 to 60% by
weight of the gum.

Useful sugar sweeteners are saccharidε-containing components commonly known in
the chewing gum art including, but not limited to, sucrose, dextrose, maltose,
dextrins, trehalose, D-tagatose, dried invert sugar, fructose, levulose, galactose, corn
syrup solids, and the like, alone or in combination.
Sorbitol can be used as a non-sugar sweetener. Other useful non-sugar sweeteners in-
clude, but are not limited to, other sugar alcohols such as mannitol, xylitol,
hydrogenated starch hydrolysates, maltitol, isomaltol, erythritol, lactitol and the like,
alone or in combination.
High-intensity artificial sweetening agents can also be used alone or in combination
with the above sweeteners. Preferred high-intensity sweeteners include, but are not
limited to sucralose, aspartame, salts of acesulfame, alitame, neotame, twinsweet,
saccharin and its salts, cyclamic acid and its salts, glycyrrhizin, dihydrochalcones,
thaumatin, monellin, stevioside and the like, alone or in combination. In order to
provide longer lasting sweetness and flavor perception, it may be desirable to
encapsulate or otherwise control the release of at least a portion of the artificial
sweetener. Techniques such as wet granulation, wax granulation, spray drying, spray
chilling, fluid bed coating, coascervation, encapsulation in yeast cells and fiber
extrusion may be used to achieve the desired release characteristics. Encapsulation of
sweetening agents can also be provided using another chewing gum component such
as a resinous compound.
Usage level of the high intensity artificial sweetener will vary considerably and will
depend on factors such as potency of the sweetener, rate of release, desired sweetness
of the product, level and type of flavor used and cost considerations. Thus, the active
level of high potency artificial sweetener may vary from about 0 to about 8 % by
weight, preferably 0.001 to about 5 % by weight. When carriers used for encapsu-
lation are included, the usage level of the encapsulated sweetener will be
proportionately higher.

Combinations of sugar and/or non-sugar sweeteners can be used in the chewing gum
formulation processed in accordance with the invention. Additionally, the softener
may also provide additional sweetness such as aqueous sugar or alditol solutions.
If a low-calorie gum is desired, a low-caloric bulking agent can be used. Examples of
low caloric bulking agents include polydextrose, Raftilose, Raftilin,
fructooligosaccharides (NutraFlora®), palatinose oligosaccharides; guar gum
hydrolysates (e.g. Sun Fiber®) or indigestible dextrins (e.g. Fibersol®). However,
other low-calorie bulking agents can be used.
The chewing gum according to the present invention may contain aroma agents and
flavoring agents including natural and synthetic flavorings e.g. in the form of natural
vegetable components, essential oils, essences, extracts, powders, including acids
and other substances capable of affecting the taste profile. Examples of liquid and
powdered flavorings include coconut, coffee, chocolate, vanilla, grape fruit, orange,
lime, menthol, liquorice, caramel aroma, honey aroma, peanut, walnut, cashew,
hazelnut, almonds, pineapple, strawberry, raspberry, tropical fruits, cherries,
cinnamon, peppermint, wihtergreen, spearmint, eucalyptus, and mint, fruit essence
such as from apple, pear, peach, strawberry, apricot, raspberry, cherry, pineapple,
and plum essence. The essential oils include peppermint, spearmint, menthol,
eucalyptus, clove oil, bay oil, anise, thyme, cedar leaf oil, nutmeg, and oils of the
fruits mentioned above.
The chewing gum flavor may be a natural flavoring agent, which is freezε-dried, pre-
ferably in the form of a powder, slices or pieces or combinations thereof. The particle
size may be less than 3 mm, less than 2 mm or more preferred less than 1 mm, calcu-
lated as the longest dimension of the particle. The natural flavoring agent may in a
form where the particle size is from' about 3 fim to 2 mm, such as from 4 \im to 1

mm. Preferred natural flavoring agents include seeds from fruit e.g. from strawberry,
blackberry and raspberry.
Various synthetic flavors, such as mixed fruit flavors may also be used in the present
chewing gum centers. As indicated above, the aroma agent may be used in quantities
smaller than those conventionally used. The aroma agents and/or flavors may be used
in the amount from 0.01 to about 30% by weight of the final product depending on
the desired intensity of the aroma and/or flavor used. Preferably, the content of
aroma/flavor is in the range of 0.2 to 3% by weight of the total composition.
In an embodiment of the invention, the flavoring agents comprise natural and
synthetic flavorings in the form of natural vegetable components, essential oils,
essences, extracts, powders, including acids and other substances capable of affecting
the taste profile.
Further chewing gum ingredients, which may be included in the chewing gum
according to the present invention, include surfactants and/or solubilisers, especially
when pharmaceutically or biologically active ingredients are present. As examples of
types of surfactants to be used as solubilisers in a chewing gum composition
according to the invention, reference is made to H.P. Fiedler, Lexikon der Hilfstoffe
fur Pharmacie, Kosmetik und Angrenzende Gebiete, pages 63-64 (1981) and the lists
of approved food emulsifiers of the individual countries. Anionic, cationic,
amphoteric or non-ionic solubilisers can be used. Suitable solubilisers include
lecithin, polyoxyethylene stearate; polyoxyethylene sorbitan fatty acid esters, fatty
acid salts, mono and diacetyl tartaric acid esters of mono and diglycerides of edible
fatty acids, citric acid esters of 'mono and diglycerides of edible fatty acids,
saccharose esters of fatty acids, polyglycerol esters of fatty acids, polyglycerol esters
of interesterified castor oil acid (E476), sodium stearoyllatylate, sodium lauryl sul-
fate and sorbitan esters of fatty acids and polyoxyethylated hydrogenated castor oil
(e.g. the product sold under the trade name CREMOPHOR), block copolymers of

ethylene oxide and propylene oxide (e.g. products sold under trade names
PLURONIC and POLOXAMER), polyoxyethylene fatty alcohol ethers,
polyoxyethylene sorbitan fatty acid esters, sorbitan esters of fatty acids and
polyoxyethylene steraric acid esters.
Particularly suitable solubilisers are polyoxyethylene stearates, such as for instance
polyoxyethylene(8)stearate and polyoxyethylene(40)stearate, the polyoxyethylene
sorbitan fatty acid esters sold under the trade name TWEEN, for instance TWEEN
20 (monolaurate), TWEEN 80 (monooleate), TWEEN 40 (monopalmitate), TWEEN
60 (monostearate) or TWEEN 65 (tristearate), mono and diacetyl tartaric acid esters
of mono and diglycerides of edible fatty acids, citric acid esters of mono and
diglycerides of edible fatty acids, sodium stearoyllatylate, sodium laurylsulfate,
polyoxyethylated hydrogenated castor oil, blockcopolymers of ethylene oxide and
propyleneoxide and polyoxyethylene fatty alcohol ether. The solubiliser may either
be a single compound or a combination of several compounds. In the presence of an
active ingredient, the chewing gum may preferably also comprise a carrier known in
the art.
Emulsifiers, which are used as softeners may include tallow, hydrogenated tallow,
hydrogenated and partially hydrogenated vegetable oils, cocoa butter, glycerol
monostearate, glycerol triacetate, lechithin, mono-, di-and triglycerides, acetylated
monoglycerides, fatty acids (e.g. stearic, palmitic, oleic and linoleic acids), and com-
binations thereof.
According to an embodiment of the invention, the chewing gum may comprise a'
pharmaceutically, cosmetically or biologically active substance. Examples of such
active substances, a comprehensive list of which is found e.g. in WO 00/25598,
which is incorporated herein by reference,

The active agents to be used in connection with the present invention may be any
substance desired to be released from the chewing gum. If an accelerated rate of
release is desired, corresponding to the effect obtained for the flavor, the primary
substances are those with limited water solubility, typically below 10g /100 ml
including substances which are entirely water insoluble. Examples are medicines,
dietary supplements, oral compositions, anti-smoking agents, highly potent
sweeteners, pH adjusting agents, etc.
Further examples of active ingredients include paracetamol, benzocaine, cinnarizine,
menthol, carvone, coffeine, chlorhexidinε-di-acetate, cyclizine hydrochloride, 1,δ-
cineol, nandrolone, miconazole, mystatine, aspartame, sodium fluoride, nicotine,
saccharin, cetylpyridinium chloride, other quaternary ammonium compounds,
vitamin E, vitamin A, vitamin P, glibenclamide or derivatives thereof, progesterone,
acetylsalicylic acid, dimenhydrinate, cyclizine, metronidazole, sodium hydrogen-
carbonate, the active components from ginkgo, the active components from propolis,
the active components from ginseng, methadone, oil of peppermint, salicylamide,
hydrocortisone or astemizole.
Examples of active agents in the form of dietary supplements are for instance salts
and compounds having the nutritive effect of vitamin B2 (riboflavin), B12, folic acid,
niacine, biotine, poorly soluble glycerophosphates, amino acids, the vitamins A, D, E
and K, minerals in the form of salts, complexes and compounds containing calcium,
phosphorus, magnesium, iron zinc, copper, iodine, manganese, chromium, selenium,
molybdenum, potassium, sodium or cobalt.
Furthermore, reference is made to lists of nutritients accepted by the authorities in
different countries such as for instance US code of Federal Regulations, Title 21,
Section 182.5013.182 5997 and 1.82.8013-182.8997.
Examples of active agents in the form of compounds for the care or treatment of the

Colorants and whiteners may include FD & C-type dyes and lakes, fruit and
vegetable extracts, titanium dioxide, and combinations thereof.
Materials to be used for the abovε-mentioned encapsulation methods for sweeteners
might e.g. include Gelatine, Wheat protein, Soya protein, Sodium caseinate, Caseine,
Gum arabic, Mod. starch, Hydrolyzed starches (maltodextrines), Alginates, Pectin,
Carregeenan, Xanthan gum, Locus bean gum, Cbitosan, Bees wax, Candelilla wax,
Carnauba wax, Hydrogenated vegetable oils, Zein and/or Sucrose.
Generally, it is preferred that the chewing gum and the gum bases prepared
according to the invention are based solely on biodegradable polymers.
However, within the scope of the invention, minor amounts of conventional synthetic
chewing gum elastomers or elastomer plasticizers, examples of which are mentioned
below, may be applied.'
Examples of such generally non-biodegradable synthetic resins include polyvinyl
acetate, vinyl acetatε-vinyl laurate copolymers and mixtures thereof. Examples of
non-biodegradable synthetic elastomers include, but are not limited to, synthetic
elastomers listed in Food and Drug Administration, CFR, Title 21, Section 172,615,
the Masticatory Substances, Synthetic) such as polyisobutylene. e.g. having a gel
permeation chromatography (GPC) average molecular weight in the range of about
10,000 to 1,000,000 including the range of 50,000 to 80,000, isobutylenε-isoprene
copolymer (butyl elastomer), styrenε-butadiene copolymers e.g. having styrenε-
butadiene ratios of about 1:3 to 3:1, polyvinyl acetate (PVA), e.g. having a GPC
average molecular weight in the range of 2,000 to 90,000 such as the range of 3,000
to 80,000 including the range of 30,000 to 50,000, where the higher molecular
weight polyvinyl acetates are' typically used in bubble gum base, polyisoprene,
polyethylene, vinyl acetatε-vinyl laurate copolymer e.g. having a vinyl laurate

content of about 5 to 50% by weight such as 10 to 45% by weight of the copolymer,
and combinations hereof.
It is common in the industry to combine in a gum base a synthetic elastomer having a
high molecular weight and a synthetic elastomer having a low molecular weight.
Examples of such combinations of are polyisobutylene and styrenε-butadiene,
polyisobutylene and polyisoprene, polyisobutylene and isobutylenε-isoprene co-
polymer (butyl rubber) and a combination of polyisobutylene, styrenε-butadiene
copolymer and isobutylene isoprene copolymer, and all of the above individual
synthetic polymers in admixture with polyvinyl acetate, vinyl acetatε-vinyl laurate
copolymers, respectively and mixtures thereof.
Examples of natural resins, which should preferably not be applied in the chewing
gum according to the present invention are: Natural rosin esters, often referred to as
ester gums including as examples glycerol esters of partially hydrogenated rosins,
glycerol esters of polymerised rosins, glycerol esters of partially dimerized rosins,
glycerol esters of tally oil rosms/pentaerythritol esters of partially hydrogenated
rosins, methyl esters of rosins, partially hydrogenated methyl esters of rosins,
pentaerythritol esters of rosins, synthetic resins such as terpene resins derived from
alpha-pinene, beta-pinene, and/or d-limonene, and natural terpene resins.
In general, chewing gum may be manufactured by sequentially adding the various
chewing gum ingredients to a commercially available mixer known in the art. After
the initial ingredients have been thoroughly mixed, the chewing gum mass is
discharged from the mixer and shaped into the desired form such as by rolling into
sheets and cutting into sticks, extruded into chunks or casting into pellets.
Generally, the ingredients may be mixed by first melting the gum base and adding it
to the running mixer. Colors, active agents and/or emulsifiers may also be added at
this time. A softener such as glycerin, may also be added at this time, along with

syrup and a portion of the bulking agent/sweetener. Further portions of the bulking
agent/sweetener may then be added to the mixer. A flavoring agent is typically added
with the final portion of the bulking agent/sweetener. A high-intensity sweetener is
preferably added after the final portion of bulking agent and flavor has been added.
The entire mixing procedure typically takes from five to fifteen minutes, but longer
mixing times may sometimes be required. Those skilled in the art will recognize that
many variations of the above described procedure may be followed. Including the
onε-step method described in US patent application 2004/0115305 hereby
incorporated as reference. Chewing gums are formed by extrusion, compression,
rolling and may be centre filled with liquids and/or solids in any form.
The chewing gum according to the present invention may also be provided with an
outer coating, which may be a hard coating, a soft coating, a film coating, or a
coating of any type that is known in the art, or a combination of such coatings. The
coating may typically constitute 0.1 to 75 percent by weight of a coated chewing
gum piece.
One preferred outer coating type is a hard coating, which term is including sugar
coatings and sugar-free (or sugarless) coatings and combinations thereof The object
of hard coating is to obtain a sweet, crunchy layer, which is appreciated by the
consumer and to protect the gum centers. In a typical process of providing the
chewing gum centers with a protective sugar coating the gum centers are
successively treated in suitable coating equipment with aqueous solutions of
crystallizable sugar such as sucrose or dextrose, which, depending on the stage of
coating reached, may contain other functional ingredients, e.g. fillers, colors, etc.
In one presently preferred embodiment/the coating agent applied in a hard coating
process is a sugarless coating agent, e.g. a polyol including as examples sorbitol,

maltitol, mannitol, xylitol, erythritol, lactitol and isomalt or e.g. a mono- di-saccha-
ride including as example trehalose.
Or alternatively a sugar free soft coating e.g. comprising alternately applying to the
centres a syrup of a polyol or a mono- di-saccharide, including as examples sorbitol,
maltitol, mannitol, xylitol, erythritol, lactitol, isomalt and trehalose.
In further useful embodiments a film coating is provided by film-forming agents
such as a cellulose derivative, a modified starch, a dextrin, gelatine, zein, shellec,
gum arabic, a vegetable gum, a synthetic polymer, etc. or a combination thereof.
In an embodiment of the invention, the outer coating comprises at least one additive
component selected from the group comprising of a binding agent, a moisturε-
absorbing component, a film-forming agent, a dispersing agent, an antisticking
component, a bulking agent, a flavoring agent, a coloring agent, apharmaceutically
or cosmetically active component, a lipid component, a wax component, a sugar, an
acid
t"
A coated chewing gum center according to the invention may have any form, shape
or dimension that permits the chewing gum center to be coated using any
conventional coating process.
The gum centre of coated chewing gum' element according to the invention can have
any form, shape or dimension that permits the chewing gum centre to be coated using
any conventional coating process. Accordingly, the gum centre may be e.g. in a form
selected from a pellet, a cushion-shaped pellet, a stick, a tablet, a chunk, a pastille, a
pill, a ball and a sphere, and typically the weight of a gum center may be 0,5 to 5
grams.

The following non-limiting examples illustrate the manufacturing of a chewing gum
according to the invention.
EXAMPLE 1
Preparation of biodegradable resinous polymer with molar ratio of 97% D,L-
lactide and 3% s-caprolactone initiated with 1,2-propane diol
To a dry 100 ml glass round-bottom flask was charged 0.265g Tin(lI)-ethylhexanoate
(Aldrich 97%), 6.427g 1,2-propanediol (Aldrich 99+%), and 18.627g ε-caprolactone
(ACROS 99+%) in a dry, nitrogen purged glovε-box. The reactor was immersed
into a 130°C preheated silicone oil bath and mechanically stirred for 65 minutes and
removed from the oil bath. The polymer was drawn into a dry syringe while still hot
and 22.172g was charged into a dry 1000 ml round-bottom flask containing 678.062g
D,L-lactide (ORTEC). The flask was immersed into the 130°C preheated silicone oil
bath and mechanically stirred for 300 minutes when removed. The flask was
immediately removed from the glovε-box and completely wrapped with a prε-heated
Qlas-Col 500 watts/115 volts heating mantle regulated with a Staco Energy Products
Type 3 Variable Autotransformer set at 65% of 0-120V output. The heated vessel
was inverted allowing the final polymer product to fully discharge from the reactor
within approximately 2 minutes into a dry 1-quart metal packaging container.
Characterization of the polymer indicates Tg = 44°C (PSC, heating rate 10°C/min),
Mn = 11,650 g/mol, and Mi, = 12,420 g/mol (gel permeation chromatography with
online MALLS detector). PD - 1.07. .
EXAMPLE 2
Preparation of biodegradable resinous polymer with molar ratio of 96.5% D,L-
lactide and 3.5% s-caprolactone initiated with 1,2-propane diol
To a dry 100 ml glass round-bottom flask was charged 0.252g Tin(IT)-ethylhexanoate
(Aldrich 97%), 3.198g 1,2-propanediol (Aldrich 99+%), and 23.366g s-caprolactone

140°C). Heating and stirring are continued and methanol is continuously distilled.
The temperature slowly rises in the range 150-200°C until the evolution of methanol
ceases. Heating is discontinued and the content is allowed to cool to about 100°C.
The reactor lid is removed and the molten polymer is carefully poured into a
receiving vessel.
Characterization of the polymer indicates Tg = -30°C (DSC, heating rate 10°C/min),
Mn - 40,000g/mol and Mw = 190,000g/mol (gel permeation chromatography with
online MALLS detector).
EXAMPLES
Preparation of gum bases and chewing gums
Three different gum bases were prepared from the above polymers of examples 1 to
4 by combining the elastomeric polymer of ex. 4 with three different resinous poly-
mers as outlined in table 1:

The gum bases areprepared as follows: ••
The elastomeric polymer and resinous polymer are added to a mixing kettle provided
with mixing means like e.g. horizontally placed Z-shaped arms. The kettle has been
i
preheated for 15 minutes to a temperature of about 60-80°C. The mixture is mixed
for 10-20 minutes until the whole mixture becomes homogeneous. The mixture is
then discharged into the pan and allowed to cool to room temperature from the
discharged temperature of 60-80°C.

Based on the Tg's of the resinous components, gum bases no. 101 and 102 are in the
present text considered as high-Tg-biodegradable gum bases as compared to gum
base no. 103. In gum base no. 103, the resinous component has a Tg of about 31 °C,
which is below mouth temperature, while in gum base no. 101 and 102, the resinous
components have Tg's of 44 °C and 41 °C, which are above normal mouth
temperature.

All the chewing gums are prepared with the same overall composition, wherein only
the type of resinous component (the polymers of ex. 1,2, and 3, respectively) in the
gum base is varied. The softeners, emulsifiers and fillers may alternatively be added
to the polymers as a part of the gum base preparation.

The chewing gum products are prepared as follows:
The gum base is added to a mixing kettle provided with mixing means like e.g.
horizontally placed Z-shaped arms. The kettle has been preheated for 15 minutes to a
temperature of about 40-60°C or the chewing gum is made in one step, immediately
after preparation of gum base in the same mixer where the gum base and kettle has a
temperature of about 60-80°C.
One half portion of the sorbitol is added together with the gum base and mixed for 3
minutes. Peppermint and menthol are then added to the kettle and mixed for 1
minute. The remaining half portion of sorbitol is added and mixed for 1 minute.
Maltitol syrup is added, and then wax and filler may be added and the gum mass is
mixed well. Softeners are slowly added and mixed for 7 minutes. Then aspartame
and acesulfame are added to the kettle and mixed for 3 minutes. Xylitol is added and
mixed for 3 minutes. The resulting gum mixture is then discharged and e.g.
transferred to a pan at a temperature of 40-48 °C. The gum is then rolled and scored
into cores, sticks, balls, cubes, and any other desired shape, optionally followed by
coating and polishing processes prior to packaging.
Evidently, within the scope of the invention, other processes and ingredients may be
applied in the process of manufacturing the chewing gum.
EXAMPLE 6
Evaluation of chewing gums comprising biodegradable polymers of high Tg's -
and the effect of regulating the molecular weight
Samples of chewing gum no. 1001 and 1002 were tested by some individual test
persons, whereby the following evaluation was obtained:

It has been found that an acceptable chewing gum texture may be obtained by the use
of high-Tg-polymers as the compound providing the resinous contribution to the
chewing gum.
In the present evaluation, the samples of 1001 are judged to be the best alternative,
even though the Tg of the resinous biodegradable polymer in 1001 is a few degrees
higher than the corresponding of 1002. If any difference between the two samples
due to Tg, it would be expected that the Tg of the resinous polymer would affect
1001 to have the hardest texture. As the opposite situation is observed, the
explanation of the texture may be interpreted to be due to the difference in molecular
weight of the resinous biodegradable polymers of 1001 and 1002, respectively.
The molecular weight of the resinous polymer of 1002 is somewhat higher than of
1001, and the texture of the final chewing gum no. 1002 is somewhat harder than of
1001. Hence, it is learned that the molecular weight may have a considerable impact
on the performance of such biodegradable, polymers of higher Tgina. chewing gum.
The chewing gum formulation of 1002 should be adjusted in order to achieve a fully
acceptable texture of the chewing guitn comprising a resinous biodegradable polymer
featuring both a relatively high Tg and molecular weight. A way to adjust the present

formulation could for example be a slight lowering of the amount of resinous
biodegradable polymer or a slight increase in the amount of softener.
EXAMPLE 7
Evaluation of chewing gums
The chewing gum no. 1001 (comprising biodegradable polymer of Tg 44°C and Mn
1165Q g/mol) was then compared to the low-Tg chewing gum no. 1003 (comprising
a biodegradable polymer of Tg 31°C and Mn 6500)
Samples of 1001 and 1003 were evaluated throughout at chewing period of 7 minutes
and involving an evaluation of the initial phases A and B (A: 0-1 min. and B: 1-2
min.), the intermediate phase (4-5 min.), and the end phase (6-7 min.) of the chewing
period. The evaluation involved the following parameters: flavor, cooling, sweetness,
elasticity, volume, and softness, the chewing gum samples were tested by serving
them to 21 sensory panelists in tasting booths made in accordance with ISO 8598
standards at room temperature in small tasteless plastic cups with randomized 3-
figure codes. For each of the parameters tested, the panelists were required to provide
their assessments according to an arbitrary scale of 0-15, with 0 being the lowest
rating and 15 being the highest rating. Between each sample tested, the panelists
were allowed a break of 3 minutes.

Generally, the above evaluation reveals surprising results for the samples of chewing
gum no. 1001. It was surprising, that the polymer with a Tg of 44°C, which is well
above human body temperature, were actually fully applicable in chewing gums. In
particular, it is a remarkable, that the properties of chewing gum no. 1001 were
basically on the same level as chewing gum no. 1003 regardless of the different Tg's.
The experiment discloses that a biodegradable polymer of high Tg, contrary to the
expectations within the art, may be Used in a chewing gum in a rather large amount,
without compromising the texture considerably.
The above table 4 summarizes by average numbers the evaluation given by the
sensory panel. However, based on Hie assertions made by the 21 sensory panelists it
was furthermore evaluated, on which parameters small differences were significant.

In table 5 the evaluation results are represented by five different levels:
2 designates that 1001 is significantly unproved with respect to 1003.
1 designates that indications of differences in favor of the 1001 samples compared
to 1003 samples was observed.
0 designates that there was found no considerable difference between 1001 and
1003,
-1 designates that 1001 shows indications of difference is observed, and that the
indication of difference the properties of 1001 was not as good as 1003.
-2 designates that there is a significant difference between 1001 and 1003 in favor of
1003.

Only the softness was in all chewing gum phases judged to be significantly inferior
in 1001 compared to 1003. The level of sweetness was equal between the two
chewing gum types in the initial phase, but in the intermediate and end phase, 1001
was apparently loosing sweetness sooner than 1003. With regard to the rest of the
parameters, flavor, cooling, elasticity, and volume, it is noteworthy, that the general
picture was that the eventual differences weren't significant.

It is understood from the experiments, that a biodegradable polyester featuring a Tg
well above mouth temperature, may be fully applicable as a resinous compound in a
chewing gum. Actually, based on the experiments, it is believed that the strength of
such a resinous biodegradable polymer is increased by an increase in the Tg. In other
words, the function as a resinous compound in chewing gum may be augmented and
in some formulations improved by a higher Tg. Thus, a biodegradable polymer
having a Tg above mouth temperature is found to have great properties as elastomer
plasticizer, ie. elastomer solvent in chewing gum.
It should furthermore be noted, that it is possible to avoid natural resins and natural
rubber, by the application of a resinous biodegradable polymer according to the
invention instead.
EXAMPLE 8
Biodegradable resinous homo-polymer with a high Tg
A polymerization similar to example 1 was performed to prepare a biodegradable
resinous polymer polymerized from only one monomer type, D,L-lactide to make a
100%-lactidε-based polymer.'
Characterization of the polymer indicates Tg about 40-45°C (DSC, heating rate
10°C/min), Mn = 6,800g/mol and Mw = 7,4P0g/mol (gel permeation
chromatography with online MALLS detector).
It is acknowledged that mis polymer is also applicable as a resinous compound in a
chewing gum formulation 'corresponding to example 5. The chewing gum is
chewable without further softening, and the chewing gum texture may be adjusted by
altering the molecular weight of the lactidε-polymer to be rather low compared to
resinous biodegradable polymers of a lower Tg such as 31 °C.

EXAMPLE 9
A homopolymer by NatureWorks® PLA 4060 D (amorph) poly D,L-lactide was
provided as a resin. The homopolymer has a Tg of about 56°C. ( Mn ~ 100,000)
EXAMPLE 10
A homopolymer by NatureWorks® PLA 5500 D (amorph) poly D,L-lactide was
provided as a resin. The homopolymer has a Tg of about 50°C (Mn ~ 50,000)
EXAMPLE 11
Preparation of gum bases
The process of preparing gum bases is carried out in the following way: The gum
base components are added to a mixing kettle provided with mixing means like e.g.
horizontally placed Z-shaped arms. The kettle has been preheated to a temperature of
about 140°C. The rnixture is mixed for 30-120 minutes until the whole mixture
becomes homogeneous. The mixture is then discharged into the pan and allowed to
cool to room temperature.

EXAMPLE 12
Preparation of chewing gum
The gum bases of example 11 were used in the preparation of peppermint flavored
chewing gum formulations 1004 to 1006 with the basic formulations shown in table
7 and where gum base 104 is applied for the preparation of chewing gum 1004, gum
base 105 is applied for the preparation of chewing gum 1005 and so forth.

The softeners, emulsifiers and fillers may alternatively be added to the polymers as a
part of the gum base preparation.
EXAMPLE 13:
Evaluation of the chewing gum of table 7.
The texture of the chewing gums of table 7 was evaluated.
It was generally observed that the texture was well compensated by the modified
softening system and that' the texture of 1005 and 1006 were acceptable and
comparable to 1004.

We claim:
1. Chewing gum comprising at least one biodegradable polymer in an amount of
from 0.1 % to 95 %, said biodegradable polymer such as herein described having a
glass transition temperature (Tg) 38°C to 90°C, wherein said chewing gum
comprising said at least one biodegradable polymer further comprises at least one
elastomeric compound such as herein described, and wherein said biodegradable
polymer has a plasticizing effect on said elastomeric compound.
2. Chewing gum as claimed in claim 1, wherein said chewing gum comprises said at
least one biodegradable polymer in an amount of from 2 to 60 % by weight.
3. Chewing gum as claimed in any of the claim 1 or 2, wherein said chewing gum is
substantially free of natural resins.
4. Chewing gum as claimed in any of the claims 1-3, wherein said chewing gum
comprises said biodegradable polymer in an amount in the range of 2 to 50 %.
5. Chewing gum as claimed in any of the claims 1-4, wherein said chewing gum
comprises said biodegradable polymer in an amount in the range of 5 to 40 %,
preferably in the range of 10 to 30 %.
6. Chewing gum as claimed in any of the claims 1-5, wherein said chewing gum
comprises said biodegradable polymer in an amount in the range of 5 to 25 %.
7. Chewing gum as claimed in any of the claims 1-6, wherein said biodegradable
polymer has a glass transition temperature (Tg) above 40°C.
8. Chewing gum as claimed in any of the claims 1-7, wherein said biodegradable
polymer has a glass transition temperature in the range of 41°C to 75°C.
9. Chewing gum as claimed in any of the claims 1-8, wherein said biodegradable
polymer has a glass transition temperature in the range of 42°C to 65°C.

10. Chewing gum as claimed in any of the claims 1-9, wherein said biodegradable
polymer has a glass transition temperature in the range of 43°C to 48°C
11. Chewing gum as claimed in any of the claims 1-10, wherein said chewing gum
comprises less than approximately 5% by weight of natural resins, preferably less
than 3% by weight and most preferably less than 2% by weight of said chewing gum.
12. Chewing gum as claimed in any of the claims 1-11, wherein said biodegradable
polymer has a molecular weight (Mn) in the range of 500 to 22000 g/mol, preferably
in the range of 500 to 15000 g/mol.
13. Chewing gum as claimed in any of the claims 1-12, wherein said biodegradable
polymer is a polyester.
14. Chewing gum as claimed in any of the claims 1-13, wherein said biodegradable
polyester polymer is obtainable by ring-opening polymerization of cyclic monomers.

15. Chewing gum as claimed in any of the claims 1-14, wherein said cyclic
monomers are selected from the group of cyclic esters and cyclic carbonates.
16. Chewing gum as claimed in any of the claims 1-15, wherein said cyclic
monomers are selected from the group of D,L-lactide, L-lactide, glycolide, δ-
caprolactone, δ-valerolactone, trimethylene carbonate (TMC) and dioxanone.

17. Chewing gum as claimed in any of the claims 1-16, wherein at least one of said
cyclic monomers is a high-Tg-inducing monomer.
18. Chewing gum as claimed in any of the claims 1-17, wherein said polyester is a
polymer obtainable by the polymerization of one single type of high-Tg-inducing
monomers.
19. Chewing gum as claimed in any of the claims 1-18, wherein said polyester is a
copolymer obtainable by the polymerization of at least two different high-Tg-
inducing monomers.

20. Chewing gum as claimed in any of the claims 1-19, wherein said polyester is a
copolymer obtainable by the polymerization of at least one low-Tg-inducing
monomer with at least one high-Tg-inducing monomer.
21. Chewing gum as claimed in any of the claims 1-20, wherein the molar ratio of
the at least one high-Tg-inducing monomer to the at least one low-Tg-inducing
monomer is in the range of 75/25 to 99/1, preferably in the range of 85/15 to 99/1.
22. Chewing gum as claimed in any of the claims 1-21, wherein the molar ratio of
the at least one high-Tg-inducing monomer to the at least one low-Tg-inducing
monomer is in the range of 90/10 to 99/1, preferably in the range of 95/5 to 99/1.
23. Chewing gum as claimed in any of the claims 1-22, wherein the molar ratio of
the at least one high-Tg-inducing monomer to the at least one low-Tg-inducing
monomer is in the range of 95/5 to 98/2.
24. Chewing gum as claimed in any of the claims 1-23, wherein said at least one
high-Tg-inducing monomer is selected from the group of monomers comprising D,L-
lactide, L-lactide and glycolide.
25. Chewing gum as claimed in any of the claims 1-24, wherein said at least one
low-Tg-inducing monomer is selected from the group of monomers comprising ε-
caprolactone, 5-valerolactone, trimethylene carbonate (TMC) and dioxanone.
26. Chewing gum as claimed in any of the claims 1-25, wherein said ring-opening
polymerization is initiated by one or more initiators.
27. Chewing gum as claimed in any of the claims 1-26, wherein said initiators
comprise 0.01 to 1.0 % by weight of said biodegradable polyester polymer.
28. Chewing gum as claimed in any of the claims 1-27, wherein at least 50 mol %,
preferably at least 70 mol % of said initiators are difunctional.

29. Chewing gum as claimed in any of the claims 1-28, wherein said polyester
polymer is substantially linear.
30. Chewing gum as claimed in any of the claims 1-29, wherein said substantially
linear polyester polymer comprises above 50 percent linear polymer chains.
31. Chewing gum as claimed in any of the claims 1-30, wherein said substantially
linear polyester polymer comprises above 70 percent linear polymer chains.
32. Chewing gum as claimed in any of the claims 1-31, wherein said substantially
linear polyester polymer comprises above 80 percent linear polymer chains.
33. Chewing gum as claimed in any of the claims 1-32, wherein said biodegradable
polyester polymer is obtainable by condensation polymerization of polyfunctional
acids or derivatives thereof and/or polyfunctional alcohols or derivatives thereof.
34. Chewing gum as claimed in any of the claims 1-33, wherein said polyfunctional
acids are selected from the group of lactic acids and glycolic acids.
35. Chewing gum as claimed in any of the claims 1-34, wherein said polyfunctional
acids are polyhydroxycarboxylic acids or hydroxycarboxylic acids.
36. Chewing gum as claimed in any of the claims 1-35, wherein said chewing gum
comprises an elastomeric compound in an amount of at least 5 %, preferably at least
10 % by weight of the chewing gum.
37. Chewing gum as claimed in any of the claims 1-36, wherein said at least one
elastomeric compound is a biodegradable elastomer.
38. Chewing gum as claimed in any of the claims 1-37, wherein said biodegradable
elastomer is obtainable by the polymerization of at least one alcohol or derivative
thereof and at least one carboxylic acid or derivative thereof.

39. Chewing gum as claimed in any of the claims 1-38, wherein the water content is
less than 3 %, preferably less than 1.5 %, and most preferably less than 1 % by
weight of the chewing gum.
40. Chewing gum as claimed in any of the claims 1-39, wherein said chewing gum
comprises one or more chewing gum ingredients selected from the group comprising
flavoring agents, sweetening agents, fillers, softeners, emulsifiers, and active
ingredients.
41. Chewing gum as claimed in any of the claims 1-40, wherein said flavoring agents
comprise natural and synthetic flavorings in the form of natural vegetable
components, essential oils, essences, extracts, powders, including acids and other
substances capable of affecting the taste profile.
42. Chewing gum as claimed in any of the claims 1-41, wherein said chewing gum
comprises flavor in an amount of 0.01 to 25 wt %, preferably in an amount of 0.1 to
5 wt %, said percentage being based on the total weight of the chewing gum.
43. Chewing gum as claimed in any of the claims 1-42, wherein the chewing gum
comprises at least one softener in an amount of 0 to 20 % by weight of the chewing
gum, more typically 0 to 10 % by weight of the chewing gum.
44. Chewing gum as claimed in any of the claims 1-43, wherein the amount of
emulsifier is in the range of 0 to 18 % by weight of the chewing gum.
45. Chewing gum as claimed in any of the claims 1-44, wherein said sweetening
agents are selected from the group comprising bulk sweeteners, and high intensity
sweeteners, and combinations thereof.
46. Chewing gum as claimed in any of the claims 1-45, wherein the chewing gum
comprises sugar.
47. Chewing gum as claimed in any of the claims 1-46, wherein the chewing gum is
sugar free.

48. Chewing gum as claimed in any of the claims 1-47, wherein said bulk sweeteners
comprises an amount of 5 to 95%, preferably 20 to 80% by weight of the chewing
gum.
49. Chewing gum as claimed in any of the claims 1-48, wherein the chewing gum
comprises high intensity sweeteners in an amount of 0 to 1.2 %, preferably 0.1 to 0.6
% by weight of the chewing gum.
50. Chewing gum as claimed in any of the claims 1-49, wherein the chewing gum
comprises filler in an amount of 0 to 50% by weight of the chewing gum, more
typically 10 to 40 % by weight of the chewing gum.
51. Chewing gum as claimed in any of the claims 1-50, wherein the chewing gum
comprises at least one coloring agent.
52. Chewing gum as claimed in any of the claims 1-51, wherein said chewing gum
ingredients comprise active ingredients.
53. Chewing gum as claimed in any of the claims 1-52, wherein said chewing gum is
coated with an outer coating selected from the group comprising hard coating, soft
coating and edible film-coating.
54. Chewing gum as claimed in any of the claims 1-53, wherein the outer coating
comprises at least one additive component selected from the group comprising a
binding agent, a moisture absorbing component, a film forming agent, a dispersing
agent, an antisticking component, a bulking agent, a flavoring agent, a coloring
agent, a pharmaceutically or cosmetically active component, a lipid component, a
wax component, a sugar, an acid and an agent capable of accelerating the after-
chewing degradation of the degradable polymers.
55. Chewing gum as claimed in any of the claims 1-54, wherein said biodegradable
polymer has a molecular weight (Mn) in the range of 500 to 400,000 g/mol,
preferably in the range of 500 to 200,000 g/mol (Mn).

56. Chewing gum as claimed in any of the claims 1-55, wherein said biodegradable
polymer has a molecular weight (Mn) in the range of 500 to 150,000 g/mol.
57. Chewing gum as claimed in any of the claims 1-56, wherein said biodegradable
polymer has a molecular weight (Mn) of less than 60,000 g/mol.
58. Chewing gum as claimed in any of the claims 1-57, wherein said chewing gum
comprises an elastomeric compound in an amount of at least 0.5 %, preferably at
least 1 % by weight of the chewing gum.
59. Chewing gum as claimed in any of the claims 1-58, wherein said chewing gum
comprises an elastomeric compound in an amount of at least 5 %, preferably at least
8 % by weight of the chewing gum.
60. Chewing gum as claimed in any of the claims 1-59, wherein said chewing gum
comprises an elastomeric compound in an amount within the range of 1% to 40% by
weight of the chewing gum.

ABSTRACT

BIODEGRADABLE CHEWING GUM COMPRISING
BIODEGRADABLE POLYMER WITH HIGH GLASS
TRANSITION TEMPERATURE
The invention discloses a chewing gum comprising at least one biodegradable
polymer in an amount of from 0.1 % to 95 %, said biodegradable polymer such as
herein described having a glass transition temperature (Tg) 38°C to 90°C, wherein
said chewing gum comprising said at least one biodegradable polymer further
comprises at least one elastomeric compound such as herein described, and wherein
said biodegradable polymer has a plasticizing effect on said elastomeric compound.